|Source and model
|Analogue Solutions LFO-NZ
|Analogue Systems RS80 VCLFO
||RS85 £110 12HP Extended LFO. Third range
added for super slow sweeps
|Elby Utility LFO
|Elby Super Psycho LFO
|MFB Dual LFO
|Plan B The Model 37 ELF LFO
[include subharmonic, though not an LFO, plus other relevant Doepfer items
|Analogue Solutions LFO-NZ - VC LFO / Noise
An LFO module with 2 separate waveform outputs, out of a
choice of 4. Use an LFO to control a VCO (to create vibrato), a VCA (for
tremelo) or to control a filter's cut-off frequencer (wah-wah /filter
sweep). Use it any where you want to change a module's performance over
Speed This sets the LFO frequency
Ramp / Reverse Ramp Level / Select Switch Sets the output level to the Ramp
out jack of the Ramp signal. Pull the control out to select Reverse Ramp.
Triangle / Square Level / Select Switch Sets the output level to the
Triangle out jack of the Trianlge signal. Pull the control out to select
Sockets Ramp / Reverse Ramp Outputs the Ramp or Rev.Ramp signal depending
which is selected.
Triangle / Square Outputs the Triangle or Square signal depending which is
Noise Direct output of a white noise signal. Use this as a control source
for interesting effects, or as an audio source for wind or percussive sounds
when used with a filter/EG/VCA (such as our SY01)
Frequency CV In This is a control voltage input. The level of the input
voltage controls the speed of the LFO. This is good for creating even more
interesting LFO effects. Feed the output of an envelope, like our EG02, into
here for an LFO speed that changes over time. Or use a CV sequencer such as
the SQ8 to change the speed on each beat.
There is also a LED indicator to show LFO speed.
||Analogue Systems RS80 VCLFO
VC LFO: Square, Saw (variable wave shape), Sine, Tri, all waveform outputs
available, +gate/reset i/p (sync), Hi/Lo range (Hi into audio range), speed
Not all periodic oscillations occur within the range of audible frequencies,
but this does not mean that you can not hear them. For example, a
violinist’s vibrato may take the form of an oscillation at, say, 5Hz, while
the growl produced by over-blowing a brass instrument may occur at 18Hz.
Even in isolation, you may hear a periodic waveform at subsonic frequencies
- for example, a clock oscillator with an output of 1Hz will sound like a
series of repeating clicks. (Strictly speaking, these have a high bandwidth
due to the transient nature of the waveform, and you would not hear a sine
wave at the same frequency, but that is not the point.)
Synthesisers have a class of oscillators - Low Frequency Oscillators (LFOs)
- that create these, and many other, effects. They can add vibrato to a
sound, produce growl, act as low frequency clocks and, on some synthesisers,
double as audio frequency oscillators.
The RS80 is a flexible LFO with an extremely low minimum frequency (one
cycle every 50 seconds) that allows you to create a variety of slowly
varying modulations and effects. Its maximum frequency lies in the middle of
the audio range. The RS80 can, therefore, be used in three ways: as a low
frequency modulator; as an audio frequency modulator; and as a secondary
sound source. It is therefore vital that, just like a primary audio
oscillator, the RS80 exhibits pitch stability, waveform accuracy, and a lack
of unwanted noise and/or distortion.
The operation of an LFO may be divided into three major categories: its
frequency, its waveform, and its level.
FREQUENCY The FREQUENCY knob has two ranges:
HIGH Turning the FREQUENCY control from its minimum to its maximum will
cause the RS80 to produce its upper range of frequencies from 3Hz to
LOW Turning the FREQUENCY control from its minimum to its maximum will cause
the RS80 to produce its lower range of frequencies from 0.02Hz to 5Hz. #
You may control the LFO rate by applying a suitable CV to the LINEAR CV IN
socket. This conforms to the Hz/Volt standard used by Yamaha and most Korg
monosynths. If you use it as a conventional oscillator you will find that
the it produces a different tone to the RS90, adding flexibility to the
Waveforms The RS80 generates four waveforms simultaneously. The first two of
these are the sine wave and the triangle wave, which are often used for
imitating acoustic characteristics such as vibrato and tremolo. The square
wave is suitable for acoustic effects such as trills, as well as for
controlling many other aspects of the synthesiser. Finally, there is the
sawtooth wave, which can assume both rising- and falling- shapes.
SINE This has no associated level control and, in normal use (i.e. with no
oscillator sync applied), it outputs a ±5V sine wave at the current LFO
TRIANGLE The level of the triangle wave is controlled using the associated
LEVEL control, and has a maximum output of ±5V.
SQUARE WAVE The level of the square wave is controlled using the associated
LEVEL control, and has a maximum output of ±5V.
SAWTOOTH The level of the sawtooth wave is controlled using the associated
LEVEL control, and has a maximum output of ±5V. The sawtooth waveform can be
inverted from a rising sawtooth to a falling sawtooth waveform by turning
the LEVEL control from its fully anticlockwise position through to its most
clockwise position. No output will be obtained when the knob is at its "12
Reset In The RS80 offers a reset input ('sync') that allows you to
re-initialise the LFO waveform by applying a second waveform at the RESET
input. This re-initialises the LFO waveform every time a positive-going
voltage is detected. If the reset signal is a low-frequency periodic
waveform, it will retrigger the RS80. If the reset signal is a mid- or
high-frequency period waveform, it will act as a 'sync' input, increasing
the harmonic complexity of the waveform generated by the RS80. If the reset
signal is aperiodic, more complex effects will occur.
Status LED The status LED gives you a direct visual indication of the LFO
AS RS85 Extended LFO. Third range added for super slow
sweeps, centre dented pot on saw/tri output and dual led for visual feed
back of frequency and cycle.
||Bubblesound coming soon
the d-lfo consists of two identical low
frequency oscillators. lfo2 can be internally synced to lfo1 by an internal
switch. the internal trip point controls the voltage point at which the
waveform is synced; continuously from lowest up until the highest point of
the waveform. additionally, the external signal can be used as the sync
source in two modes; the sync t converts the external signal to a very
narrow pulse for a distinct sync and the sync g extracts the pulse width of
the external signal for sync with a "steady state" synced waveform. the rm/am
is a ring modulator/amplitude modulator. it is coupled to both lfos' outputs
and has a seperate output "rm-am" and input for external signal (pre-patched
to the lfo2's output).
total rate range - 100 sec to 50 usec
rate 1,2 - 30 sec to 3 msec in two ranges
waveforms - 7 basic waveforms (including 2 s/h)
rate cv - leveled, 0 to 1 volt/octave
sync trip point - 0 to 95% of waveform's amplitude
rm/am - rm/am mode switch
sync t - accepts any waveshape, 2 volts threshold, 20usec pulse width
sync g - accepts any waveshape, 2 volts threshold, any pulse width
current consumption - 75 ma
dimensions - 28.4 mm (h), 70.6 mm (b); 3 he, 12 te
this module has a maximum current draw of 75ma. it requires 12 hp/te worth
of space to fit in a eurorack frame
||Elby Designs Utility LFO
This module is a dual utility
LFO offering manually variable wave shapes. Standard waveshapes are falling
ramp variable through triangle to rising ramp, and variable pulse width. A
fixed square wave is also available, as is a combination waveshape that is
variable between the TRI/SAW output and the SQUARE. This is a MIX not a
morph. Two switches allow the variable outputs of the two LFOs to be
The Utility LFO is based on the standard integrator/schmitt
trigger oscillator core. Two pots in the integrator charge path allow for
the adjustment of speed, and along with two diodes, for the adjustment of
charge versus discharge time. Changing this ratio will allow the TRI/SAW
output to be adjusted from a falling ramp through triangle to a rising ramp.
At the same time, the output of the schmitt trigger will reflect this in the
length of its output pulse.
A 0-volt referenced comparator connected to the output of the integrator
generates a square wave as there is always an equal portion the
ramp/triangle wave above the 0-volt reference, though adjustment of the
shape of the ramp/triangle wave does change the phase of this square wave.
Following the comparator is a buffered voltage divider to bring the square
wave down to a more suitable level and also to drive one side of the
variable output mixer pot. The other side of the variable output mixer pot
is connected directly to the integrator output. The variable output is
buffered and used post mixer by another op-amp.
The JOIN switch interconnects the two VARI outputs by swapping their ramp
outputs with each other, so that each output is a combination of that LFO's
square wave with the other's ramp. The SWAP switch reverses the outputs of
the second LFO so that (when JOIN is on) one VARI output is a combination
for both square waves while the other is a combination of both ramps. When
JOIN is off, SWAP merely reverses the direction in which the second LFO's
VARI knob works.
This module has a maximum current draw of 30mA. It requires 18 HP/TE worth
of space to fit in a Eurorack frame.
||Elby Designs Super Psycho LFO
This module is a much
expanded version of the Psycho LFO, featuring six free-running oscillators,
each variable between LFO and audio ranges, two of which can be switched to
have triangular wave outputs. Each oscillator can be switched between low
and high ranges, as well as off, and also has a rate LED, to allow visual
determination of the frequency at which it is running. As per the original,
there are also level and glide controls.
How to use this module
This module can be used to create a range of pseudo-random modulation
voltages that can be used to generate unusual sequences, control VCFs or or
VCAs etc. When run at higher frequencies, it can be used as a series of
audio drones, or to generate complex sounds by frequency modulation a VCO.
A little on how it works:
The Super Psycho Modulation Source is a fairly simple circuit with a lot of
repetition. The circuit consists of several distinct blocks. The first are
the oscillators, each based on a section of a 40106 hex schmitt inverter and
their associated components. The switch allows extra capacitance to be
added, reducing the speed of the oscillator to a lower range. The same
switch allows the capacitor to be bypassed to the negative rail via a
protection resistor, disabling the oscillator, and setting its output to
near 0 volts. The 1M RATE pots allow the upper frequency range to extend
over a large portion of the audio spectrum, and in the lower frequency
position, to extend from sub-audio to low audio frequencies.
Two of the oscillators are equipped with voltage followers that follow the
the, roughly, triangular shape of the wave present on the oscillator
capacitors. The 100k and 360k resistors on the output, when coupled to the
virtual ground summing node of the following mixer, via the switch, correct
the amplitude and offset of the triangle wave.
The next block is a traditional op amp inverting mixer stage. Signals from
the six oscillators are mixed through 470k resistors, the overall gain
controlled by a 100k pot in the feedback path of the op amp.
What is interesting here is that in order to keep the output signal of the
mixer positive without the need for an additional inverting stage, the chip
used to build the six oscillators is powered from the negative rail, it's
positive power pin connected to 0V and its earth pin connected to -15V. Take
special note of this, because it is an unusual way to power a digital chip,
and inadvertent poking with a logic probe powered from the positive rail
could cause you grief!
The final stage is a simple glide circuit consisting of a potentiometer, a
capacitor and unity gain voltage follower. The switch is to allow easy
switching in and out of a pre-adjusted glide setting.
This module has a maximum current draw of 45mA. It requires 22 HP/TE worth
of space to fit in a Eurorack frame.
||MFB Dual LFO
the dual lfo module houses two individual
low frequency oscillators (lfos) used mainly for modulation purposes. each
lfo section offers three selectable waveforms, cv-input with attenuator and
a rate ranging from 10 seconds to approximately 100 hz. by applying positive
or negative voltage, this range can be widened with a factor up to 30,
resulting in extreme slow or fast modulation rates.
both lfos offer individual inputs to reset the waveform, making it possible
to synchronize to a sequencer with appropriate rate settings and separate
lfo 1 offers triangle, saw tooth down and square waveforms, lfo 2 offers
triangle, saw tooth up and sample & hold. output voltages are +/- 5 volts at
when not patched, the two cv-inputs are internally cross-wired, meaning that
lfo 1 controls the speed of lfo 2 and vice versa with both attenuators being
active to set modulation intensity.
the module has a width of 40 mm (8 te).
The Model 37 ELF LFO has an identity problem.
While specifically designed as an LFO, it's massive frequency range 1 cycle
per 30 seconds to over 20Hkz makes it the perfect candidate for utility
audio VCO applications. Incorporating a heavily-modified version of the TAU
triangle core architecture, the M37 is capable of 1v/oct tracking across
it's entire operating range when the external VC Attenuator is set to the
full clockwise position.
A phase-accurate, one-shot driven hard Sync input will stop and restart the
VCO dead in it's tracks with any input received. So unlike other VCOs, it
doesn't require a squarewave input to operate.
Switch-selectable paired output ports morph between Triangle/Square or
Positive Ramp/Pulse configurations. An LED indicates the energy level of the
Triangle/Sawtooth output port in realtime.
The M37, although housed in a small, elfin package is a complex and accurate
device and it's product page requires the level of detail a fully functional
VCO deserves. Please check back in the next few days as audio examples,
waveshape snap and application notes are added.
Calibration of the Model 37 for 1v/Oct:
While the M37 is primarily an LFO, it does pass the entire audio range and
can be set for keyboard tracking, about three octaves, in ithat audio
bandwidth. While the tracking is adjusted by Plan B, it is highly dependant
on the voltages powering the module so it is recommended you re-adjust this
limit in your own system as an on trimpo has been included t to compensate
for PSU variances.
The M37 has two trimpots. One closure to outer edge of the PCB is used to
set the symmetry or the triangle core waveform. The second, closer to the
center fo the board, is used to set the limits of the VC Freq input. To
calibrate this, insert the output of a midi to CV which generates 1v/oct
scaling into the VC Freq input of the M37 and turn it's attenuating pot
fully CW. Then use the trimpot until find the 'sweetspot' where your
specific PSU configuration will allow for the largest tracking rangel Three
octaves minimum should be obtainable